A tire using such a puncture-preventing sealant is already known from Japanese Patent Application Laid-open No. 10-71806, for example. The known puncture-preventing sealant has a viscosity set in a range of 20 to 23 dPa·s, and a thixotropy index set in a range of 5.5 to 5.8.
When a vehicle provided with a tire assembly comprising a tire using the above known puncture-preventing sealant and assembled to a wheel is traveling at a high speed exceeding 100 km/hr, for example, a vibration and/or a noise may be produced due to an unbalance of the tire assembly in some cases. Such unbalance can be overcome by the correction using a balance weight. However, when the viscosity of the sealant is low, the following problem is encountered: If the vehicle is left in a stopped state, the sealant flows to a lower portion of the sealant chamber by gravitation, whereby the tire assembly is brought again into its unbalanced state. Another problem is that even if a static balance is provided in a tire assembly comprising a tire assembled to a wheel, as commonly conducted, the sealant is moved within the sealant chamber once the vehicle travels, resulting in the balance loss again. If the viscosity of the sealant is merely increased, the following problem is encountered: It is difficult to diffuse the sealant uniformly within the sealant chamber due to the rotation of the tire caused by traveling of the vehicle, and an appropriate sealability is not provided.
Therefore, the development of a sealant has been desired, which is permitted to flow within the sealant chamber to become diffused uniformly in a traveling state of a vehicle, and is difficult to flow within the sealant chamber in a left state, whereby the balance can be prevented from being lost.